A hernia occurs when an internal part of the body, such as tissue or an organ, pushes through a weak spot or hole in the surrounding muscle or tissue wall. This can often appear as a noticeable bulge, particularly in the abdomen or groin area. While some hernias may not cause symptoms, surgical repair is frequently necessary to address the weakness and prevent further complications. Surgical mesh is a common material used during these procedures to reinforce the repair.
How Mesh Supports Hernia Repair
Surgical mesh provides a supportive structure for weakened tissues in hernia repair. The mesh acts as a scaffold, allowing the body’s own tissues to grow into and around it, creating a stronger and more durable repair. This reinforcement helps to reduce tension on the surgical site, which is important for preventing the hernia from recurring. Unlike older “tension repair” methods that relied solely on stitching tissues together, mesh provides a tension-free repair that has been shown to lower recurrence rates.
Different Kinds of Hernia Mesh
Hernia repair mesh comes in several distinct types, each with specific characteristics. Materials are chosen based on their composition, permanence, and interaction with the body, influencing their use in specific situations.
Synthetic Mesh
Permanent synthetic meshes are widely used for long-term reinforcement. Common materials include polypropylene (PP), polyester (PET), and expanded polytetrafluoroethylene (ePTFE).
Polypropylene mesh is often selected for its strength and ability to support the abdominal wall. Polyester mesh can be soft to the touch, though some reports indicate it may stiffen after implantation. Expanded PTFE is known for its inertness, which can result in less tissue inflammation.
Synthetic meshes come in heavyweight and lightweight options, varying in material density and pore size. Lightweight meshes generally have larger pores, which can allow for better tissue integration and flexibility, while heavyweight meshes provide high tensile strength.
Absorbable Mesh
Absorbable meshes provide temporary support and gradually dissolve within the body. As the mesh dissolves, the body’s own tissue grows in its place, eventually taking over the repair. Common materials include polyglycolic acid (PGA) and poly(4-hydroxybutyrate) (P4HB). Absorbable meshes are often considered for specific situations, such as when there is a risk of infection or when a permanent material is not desired. They facilitate natural tissue regeneration, potentially reducing chronic pain and foreign body reactions.
Biologic Mesh
Biologic meshes are derived from animal or human tissues, such such as porcine (pig) dermis or bovine (cow) pericardium. These meshes are typically absorbable and undergo remodeling into the patient’s own tissue. Biologic meshes are often reserved for complex cases, particularly those with contamination or infection, where synthetic meshes may be unsuitable. However, they are more costly and may have a higher recurrence rate for uncomplicated repairs.
Composite Mesh
Composite meshes combine different materials or properties to achieve specific benefits. They often feature multiple layers, with one side promoting tissue integration and another preventing adhesions to internal organs. For example, a composite mesh might combine polypropylene for strength with ePTFE for its reduced adhesion properties. This design allows for strategic placement within the body, optimizing both reinforcement and minimizing unintended tissue attachment.
How Surgeons Choose Mesh
Surgeons tailor mesh selection to each patient and hernia, as no single mesh fits all repair needs. The hernia’s characteristics are primary considerations, including its type (e.g., inguinal, umbilical, incisional), size, and exact location.
Patient factors like overall health, activity level, and underlying medical conditions (e.g., diabetes, obesity) are important, as is the risk of infection. The surgical approach (open or laparoscopic) can affect the preferred mesh shape or handling. Surgeons may also consider their own experience and familiarity with particular mesh types. Clinical evidence supporting the effectiveness and safety of specific meshes also guides the decision.
Mesh Design for Long-Term Support
Surgical mesh is engineered with specific features for lasting support in hernia repairs. Biocompatibility is a key design aspect, meaning the material integrates well with body tissues without causing significant adverse reactions.
The mesh’s pore size is a significant design element, influencing how the body’s tissues grow into the material. Larger pores (typically >1 mm) generally allow for better tissue ingrowth, less foreign body sensation, and improved flexibility. Conversely, smaller pores might lead to increased scar tissue formation, which could reduce flexibility.
Meshes are designed to offer sufficient strength to reinforce the weakened area while maintaining enough flexibility to adapt to body movements. This balance helps reduce discomfort for the patient.